1. Field of the Invention
This invention relates to an apparatus and method of cooling a heat producing electronic component. More particularly, this invention relates to a novel configuration and design for a heat exchanger providing an apparatus and method for managing low velocity fluid flow. The invention thereby expands the envelope of cooling performance provided by fluid flow over plates.
2. Discussion of Related Art
It is important to dissipate the heat produced by electrical devices in order to extend the useful life of these devices. Heat dissipation is particularly important in the case of high-power electronic components, such as microprocessors and lasers, which generate a relatively high amount of heat in a relatively small area. Conventional heat sink devices typically utilize an array of extended surfaces, such as fins, integrally formed on a common base. The array of extended surfaces project into an ambient fluid surrounding the device. The base is placed in thermal intimate contact with a heat-producing device to provide a conduction path to the fin array. Through forced or natural convection, fluid circulation around the fin array acts as the heat transfer medium for cooling the device to an operable temperature.
Designing acceptable heat exchangers to adequately dissipate the heat generated by these heat generating components is a difficult task. These electronic components are typically used within systems housed in an enclosed cabinet having a fan mounted therein. The fan is mounted so as to pull cooling fluid across the heat generating electrical components. Given their relative simplicity, traditional extruded plate fin heat exchangers are generally preferred from both cost and implementation perspectives. Traditional plate fin heat exchangers generally offer high surface area relative to their size. However, the design of the conventional plate fin heat exchanger is often inadequate for dissipating heat generated from high power electronic components. Accordingly, conventional plate fin heat exchangers with novel design layouts for providing enhanced cooling of electronic components are a preferred apparatus for providing the proper cooling of the heat generating components.
Advances have been made involving the use of narrow channel and micro-channel plate fin heat exchangers for cooling electronic components. For example, U.S. Pat. No. 5,304,846 to Azar et al., discloses a narrow-channeled heat exchanger with certain geometric relations aimed at improving the heat dissipation of the heat exchanger. Specifically, the patent teaches optimal ratios relating the height of the plate fins to the width of the channels. The ratios may be selected for optimizing the heat dissipation capabilities of the heat exchanger for a given pressure drop across the heat exchanger.
Although narrow channel heat exchangers significantly improve heat dissipation, they, like all other plate fin designs, suffer from boundary layer formation. The boundary layer consists of hydrodynamic and thermal layers which result from friction or drag which occurs when the cooling fluid and the plate fins meet. This boundary layer of hot low velocity fluid blankets the plate fin heat exchanger insulating the exchanger from cooler fluid flow, which causes a reduction in heat transfer and premature egress of fluid from the fin field. In addition, the boundary layer narrows the remaining channel available for fluid flow and causes a reduction in the volume of the fluid flow, thereby significantly reducing the productivity of the heat exchanger. Accordingly, the conventional heat exchanger incorporating the narrow channel design continues to suffer from a lower productivity due to the formation of high pressure and a boundary layer.
The Assignee has a patent application Ser. No. 08/673,802, now U.S. Pat. No. 5,957,194, hereby incorporate by reference, disclosing a heat exchanger comprising a fin field for reducing formation of high pressure within the fin field, increasing efficient heat transfer, and preventing premature egress of fluid from the fin field. This particular heat exchange design comprise fluid control and fluid ventilation designs for achieving a reduction in high pressure fluid within the fin field. Although the modifications disclosed in Assignee's pending application successfully reduce the formation of high pressure and fluid by-pass, such modifications to the individual fins can be costly and difficult to manufacture. In the best mode of Applicant's invention herein, Applicant overcomes the formation of high pressure and fluid by-pass through a novel design. The novel fluid control and fluid ventilation elements of U.S. Pat. No. 5,957,194 may be incorporated into Applicant's invention to further increase the performance of the heat exchanger within the parameters of the present invention, Accordingly, the present invention comprises a narrow channel fan tail heat exchanger for alleviating the inefficiencies associated with prior art conventional heat exchanger.
Therefore, what is desirable is a plate fin heat exchanger that reduces and/or deters formation of high pressure, prevents the premature egress of fluid from the fin field caused by formation of high pressure, minimizes boundary layer formation without increasing pressure, and enhances heat transfer. The present invention incorporating a fan tail design together with a narrow channel configuration overcomes the outstanding issues present in the prior art and achieves the theoretical limit of cooling performance provided by fluid flow over a plate fin heat exchanger.